How to globally modify the spacing in the enumerate environment?



I managed to get it working for 1 level lists:

\documentclass{memoir}

\renewenvironment{enumerate}{%
\begin{list}{%\enumerate
\addtocounter{enumi}{1}\labelenumi}{
\setlength{\itemindent}{0bp}
\setlength{\itemindent}{0bp}
\setlength{\leftmargin}{13.5bp}
\setlength{\topsep}{6bp}
}}
{\end{list}\setcounter{enumi}{0}}

\begin{document}
\begin{enumerate}
\item First level

\begin{enumerate}

\item second level

\item more
\end{enumerate}

\item Back

\item Continue

\item Done
\end{enumerate}

\end{document}

But the numbering is messed up for nested lists.

Is it really necessary that I do all of the code to handle nesting
when it's already in memoir/latex? If so, where do I copy-paste it
from?

I found the definition for the \enumerate macro and thought it could
just be used here, but it causes an error.

William
.